[Gary Kline]

My 2014 Cherokee recently had the 4wd unavailable overheated light come on one time. Then I started getting the 4wd unavailable randomly on startup going away after driving a few feet. Most recently it’s been randomly while driving but especially on startup trying to go into 4low without pressing the button. You stop and put it in neutral and it won’t shift into 4low. Once you shut it off it’s usually gone for a while. I hear there are gremlins in the ptu, but any chance it could be a wheel sensor or something else easy? I never use 4 low is there a way to deactivate it and would that even help?? I checked the oil in the rear differential recently and neither plug had shavings in the oil. This car was s kinda a beater and I’m on a budget but would like 4high if there’s a way to just have that. We do all our own auto repair here but time is the problem. Going to put it on our lift Wednesday and see if we still have 4hi along with oil sender and exhaust work.
-Greg

Hey Greg,

Welcome to the Forum! You can disable the whole 4WD/AWD system by pulling some fuses however there's no way to just disable the "Low" and keep the "High" range. there are somethings to check first though since pulling the PTU is an involved job...

• While the PTU (and more likely), the actuator on top is having an issue than the actual hardware (metal), itself. There's also the actuator on the Rear Drive Module (RDM, the rear unit) as well as the controller in the spare tire well called the Drive Train Control Module (DTCM) which is susceptible to water infiltration in the spare tire area. Check under/around your spare tire area for water/dampness. Also, there are two small storage cups to the left and right in the cargo area. Pull them out and check the felt under them for dampness. There's a known issue with this and if the water has spread to the DTCM, it can corrode the wires at the connector causing intermittent contact.

• Also, you have a 2014 so get your battery checked (you can get a free test at an Auto Zone/Advance Auto ) and also check your primary ground strap for corrosion ( https://www.jeepcherokeeclub.com/threads/ground-strap-replacement-step-by-step.250148/post-3034667 ). So many seemingly unrelated issues on the Cherokee can be tied back to a weak/failing battery or corroded, primary ground strap.

 

[Gary Kline]

One last thing... Google MOPAR RECALL FCA and go to their website, put in your VIN and see if you have the extended warranty on your PTU. Since your light comes on intermittently, it could be slipping. There's an issue with AD2 PTU's that caused an in-warranty extended warranty for a specific batch. You have a 2014 and if it was manufacturer after mid-April 2014, you probably have the extended warranty. If your PTU is slipping, it would set off the SVC 4WD light. If you have an OBD2 reader, see if you have any specific codes. The extended warranty covers specific codes. If those are present, you may be entitled to a replacement.

 

[Gary Kline]

It has a U1204-00 code lose of communication between the rdm and dtcm. If you delete the code the 4wd light goes away but just briefly. That’s as far as I’ve gotten.
-Greg

Hey Greg,

• If the only code you're getting now is a communication code between the RDM and DTCM, I'd first visually inspect your DTCM module. It's in the cargo area behind the lower threshold trim of the cargo opening adjacent to the spare tire well. To access, remove the spare tire, remove the two D rings on the sill, pull the sill out, then move the back seats to the front, then pull the rear floor/wheel well liner out. The DTCM is there to the right just inside the hatch on the passenger side. There's a documented issue of water infiltration in into the spare tire well and has known to short and/or corrode the connector on the DTCM. Also, check your spare tire well as well as pull the two small storage cups on the left and right sides when opening the lift gate. Feel the felt under there. Anything wet or damp? When checking the module, I'd pull the two connectors and inspect the wires on the connectors as well as the pins on the module itself. Any corrosion/green-white powder? If so, that could be your issue right there. You could also check the connector on the RDM but it's under the car (top side of the RDM) and not easily accessible but using a small mirror and strong light you may be able to see enough to see if you see any obvious issue on the connector. Also, there's two wires from the hydraulic fluid pump and pressure sensor under there. Make sure they're not broken/damaged (though I think you'd get a different code for those if I recall correctly).

• One last thing... since you have a 2014 with a communication issue, be sure to also check your primary ground strap. A corroded transmission ground strap can cause all sorts of drive train-related error codes : https://www.jeepcherokeeclub.com/threads/ground-strap-replacement-step-by-step.250148/post-3034667

 

[Gary Kline]

There was a good amount of ice in the spare tire well, but when we pulled the plugs to the dtcm there was some light corrosion we cleaned it up good and put it back together, still acting up thou. Suspect it may be shorted but I want to check the other end of the conections and the rdm. Does a new dtcm need to be flashed? Any good aftermarket ones? We already replaced the transmission ground strap, it was a little corroded but not to bad.
-Greg

Hey @Grega,

Yup, you've probably got a short. While you can check the RDM, I would really put my money on that DTCM. While you're back there, also check your Electric Parking Brake (EPB) module and if you have a powered (non-manual) lift gate, the Powered Lift Gate Module (PLGM). Both of those are on the driver's side and also have recalls/TSB's/TechNotes on shorting from water in the the rear well.

I don't think a new DTCM will need to be flashed to work. Do a Search using the search bar above. A couple other members have replaced theirs, I think they mentioned they didn't need to do anything. You can get one from a wrecked Cherokee of eBay or Car-Parts.com at much less than new.